The present disclosure relates to protection of element(s) of a space-based sensor from direct solar illumination and in particular to a multi-axis articulated solar light shade that protects the element(s) of a space-based sensor from direct solar illumination.
Direct solar illumination of the elements of a space-based sensor, for example, optical elements, can cause scattering of the sunlight to various parts of the space-based sensor field-of-view which can lead to degradation of the imagery by increasing photon levels impinging upon a detector. Also, direct solar illumination can cause temperature increases that distort the location, optical figure, and/or change the refractive index of the optical elements and thereby degrade the quality of sensor performance.
Conventionally, a fixed flat-panel sunshade with an integrated visor has been used to protect elements of space-based sensors from solar illumination. One example of such a sunshade is used in SBIRS (Space-Based Infrared System) satellites by Lockheed Martin. This type of fixed sunshade is attached to a space-based vehicle, for example, a spacecraft, and is used to protect elements of multiple space-based sensors on the spacecraft bus from unwanted solar illumination. Since, the sunshade is fixed to the spacecraft (i.e., does not independently move), the spacecraft is required to constantly maneuver to keep unwanted sunlight off the sensors. This increases the spacecraft system cost and complexity due to: i) the cost and complexity increases in the bus maneuvering system; ii) manpower increases at ground station; iii) cost and complexity increases of the optical bench stabilization system due to transient disturbances from bus maneuvering; and iv) cost and complexity increases of the inertial navigation system responsible for spacecraft positional knowledge and associated image processing to correct for maneuvering.
What is needed is a system and method that provides a multi-axis articulated solar light shade that protects elements of a space-based sensor from direct solar illumination without requiring the additional cost and complexity that other methods require while preventing sensor performance degradation.